Internal batch mixers

As pointed out at the beginning of the chapter, when designing a new polymer processing operation to produce a product or to blend or compound a new material, it is often desirable or necessary to work on a smaller scale such as a laboratory extruder, internal batch mixer, stirring tank, etc. The evolving model must then be scaled up or down to the actual operation. 

Internal batch mixers can sometimes be simplified to a system such as the one shown in Fig. 6.77. For h R, the system can be further simplified by unwrapping the material from the cylinder and modeling it using rectangular coordinates. 

Figure 6.77 Schematic diagram of a simplified internal batch mixer geometry.

The NPD functions for characterizing dispersive mixing in internal batch mixers were developed by Manas-Zloczower et al. (57-60) and for SSEs by Manas-Zloczower and Tadmor (61).They were formalized and generalized by Tadmor (62,63). 

Fig. 10.5 Photograph and cross-sectional schematic representation of a Banbury high-intensity internal batch mixer. The photograph shows the two elements of the drive the electrical motor and the gear reducer. Their large size is due to the very large power requirements of the mixer. [Photograph courtesy of the Farrel Company, Ansonia, CT.]...

Internal batch mixers are batch systems that have both a lower-shear homogenizing region and a localized high-shearing section. Refer to the schematic disgram in Figure 6.20. 

Studies of chemical kinetics in glassware and internal batch mixers. 

Internal batch mixers are widely used in the rubber industry. They are also used for processing plastics such as vinyl, polyolefins, ABS, and polystyrene, along with thermosets such melamines and ureas because they can hold materials at a constant temperature. 

MWCNT/PP nanocomposites were prepared by melt blending at 200°C with a rotor speed of 60 rpm using an internal batch mixer. SEM images of the fracture surface in the composites demonstrated that PS-grafted MWCNTs were dispersed well in... 

Simulating Flows in Internal Batch Mixers with 2-D Models. 871... 

This section presents various examples and applications of three-dimensional simulation using finite element and boundary element techniques. These are presented to offer the reader an idea of what is possible with the current state-of-the-art of simulation programs. As examples, the authors have chosen cases that are of great interest to the academic, as well as, the industrial research community. These are internal batch mixers, extrusion dies and extrusion mixing sections. 

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